What happens in a galvanic cell when one doesn't attach a porous disk or a salt bridge? Can someone explain in depth what happens?

if you don't attach the salt bridge, you get a build up of charge in the containers containing the anode and cathode stuff. your reaction will go more slowly and probably not as far as it would because now it has to work against an electrical gradient. systems are happy when they are neutral. the salt bridge is necessary to transfer the charged spectator ions across to different cells to keep the solution neutral. i hope that helps!!!